This is a continuing project in which human temporal bones from individuals who suffered from deafness or vertigo will be prepared for light microscopic study. Correlations are then made between the pathological findings and the deficits in auditory and vestibular function as determined by tests made prior to death of these individuals. An important aspect of the past two years work is an evaluation of the cochlear neuronal population and the correlation of population deficits with speech discrimination scores. A book on otopathology is being prepared from the material collected under the support of this grant. Furthermore, the sets of temporal sections are used for weekly conferences for teaching the staff and residents and for the teaching of pathology to post-residency fellows.